use std::{
	ffi::{CStr, CString},
	marker::PhantomData,
	ptr,
	str::from_utf8_unchecked,
};

use crate::ffi::*;

pub struct Iter<'a> {
	ptr: *const AVDictionary,
	cur: *mut AVDictionaryEntry,

	_marker: PhantomData<&'a ()>,
}

impl<'a> Iter<'a> {
	pub fn new(dictionary: *const AVDictionary) -> Self {
		Iter {
			ptr: dictionary,
			cur: ptr::null_mut(),

			_marker: PhantomData,
		}
	}
}

impl<'a> Iterator for Iter<'a> {
	type Item = (&'a str, &'a str);

	fn next(&mut self) -> Option<<Self as Iterator>::Item> {
		unsafe {
			let empty = CString::new("").unwrap();
			let entry = av_dict_get(self.ptr, empty.as_ptr(), self.cur, AV_DICT_IGNORE_SUFFIX);

			if !entry.is_null() {
				let key = from_utf8_unchecked(CStr::from_ptr((*entry).key).to_bytes());
				let val = from_utf8_unchecked(CStr::from_ptr((*entry).value).to_bytes());

				self.cur = entry;

				Some((key, val))
			}
			else {
				None
			}
		}
	}
}
